Characterization and Mitigation of Range Estimation Errors for an RTT-Based Ieee 802.11 Indoor Location System

Prieto, Javier; Bahillo, Alfonso; Franco, Santiago Mazuelas; Toledo, Rubén Mateo Lorenzo; Reguero, Patricia Fernandez; Abril, and Evaristo Jose

doi:10.2528/pierb09050502

Cited by 16 publications

(3 citation statements)

References 28 publications

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“…Determining position accurately indoors, where GPS is not reliable, has many potential applications and has been of interest for some time [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] (we use the terms "position" and "location" interchangeable). One of the latest entries in this effort is fine time measurement (FTM) of round trip time (RTT) as specified in the 2016 update of the IEEE 802.11 Wi-Fi standard (also referred to as IEEE 802.11mc) reference [9,10,12,13,16].…”

Section: Overviewmentioning

confidence: 99%

“…The contributions of the research presented here are as follows: This paper introduces: (1) "frequency diversity"-a method for doubling the accuracy of FTM RTT distance measurements; (2) the "position-dependent error" texture surface-a new way of understanding the nature of the errors in FTM RTT distance measurement; (3) analysis of the unusual properties of the errors in distance measurement in terms of properties of super-resolution algorithms; (4) recognition of the serious impact of signal delay in common building materials resulting from their high relative permittivity-arguably more important than possible multi-path effects.…”

Section: Introductionmentioning

confidence: 99%

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Doubling the Accuracy of Indoor Positioning: Frequency Diversity

Horn¹

2020

Sensors

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Determination of indoor position based on fine time measurement (FTM) of the round trip time (RTT) of a signal between an initiator (smartphone) and a responder (Wi-Fi access point) enables a number of applications. However, the accuracy currently attainable-standard deviations of 1-2 m in distance measurement under favorable circumstances-limits the range of possible applications. An emergency worker, for example, may not be able to unequivocally determine on which floor someone in need of help is in a multi-story building. The error in position depends on several factors, including the bandwidth of the RF signal, delay of the signal due to the high relative permittivity of construction materials, and the geometry-dependent "noise gain" of position determination. Errors in distance measurements have unusal properties that are exposed here. Improvements in accuracy depend on understanding all of these error sources. This paper introduces "frequency diversity," a method for doubling the accuracy of indoor position determination using weighted averages of measurements with uncorrelated errors obtained in different channels. The properties of this method are verified experimentally with a range of responders. Finally, different ways of using the distance measurements to determine indoor position are discussed and the Bayesian grid update method shown to be more useful than others, given the non-Gaussian nature of the measurement errors.

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Section: Overviewmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Doubling the Accuracy of Indoor Positioning: Frequency Diversity

Horn¹

2020

Sensors

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“…Positioning analysis [2][3][4][5][6][7][8][9][10][11][12][13][14] is essentially important in locating the objects of interest in a certain enterprise. The knowledge of the placement, movement, and coverage of a reader is fundamental in locating the objects smoothly and efficiently.…”

Section: Introductionmentioning

confidence: 99%

A Novel Positioning System Utilizing Zigzag Mobility Pattern

Reza¹,

Pillai²,

Dimyati³

et al. 2010

PIER

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Abstract-This paper proposes a new positioning system utilizing mobile readers that are programmed to move in a zigzag pattern to locate the tags. The proposed zigzag mobility pattern is able to cover an area completely within a given period, determine optimal number of required mobile readers, and find out reader placement and movement pattern. The received signal strength (RSS) model is used to exchange the information over a short range by estimating the position of the tag by means of distance information between the reader and the tag. The results obtained from this study point out that the proposed method is able to provide near exact tag position. The proposed method can achieve average error as low as 0.6 m. With this proposed method, the scanning of large areas, such as warehouses, libraries, and storage areas can be done very quickly. Mobile reader is proposed because it is cost-effective, fast, and is able to provide relatively accurate results.

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Adaptive framework for uncertainty analysis in electromagnetic field measurements

Prieto

Alonso

Rosa

et al. 2014

Radiation Protection Dosimetry

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Misinterpretation of uncertainty in the measurement of the electromagnetic field (EMF) strength may lead to an underestimation of exposure risk or an overestimation of required measurements. The Guide to the Expression of Uncertainty in Measurement (GUM) has internationally been adopted as a de facto standard for uncertainty assessment. However, analyses under such an approach commonly assume unrealistic static models or neglect relevant prior information, resulting in non-robust uncertainties. This study proposes a principled and systematic framework for uncertainty analysis that fuses information from current measurements and prior knowledge. Such a framework dynamically adapts to data by exploiting a likelihood function based on kernel mixtures and incorporates flexible choices of prior information by applying importance sampling. The validity of the proposed techniques is assessed from measurements performed with a broadband radiation meter and an isotropic field probe. The developed framework significantly outperforms GUM approach, achieving a reduction of 28% in measurement uncertainty.

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Characterization and Mitigation of Range Estimation Errors for an RTT-Based Ieee 802.11 Indoor Location System

Cited by 16 publications

References 28 publications

Doubling the Accuracy of Indoor Positioning: Frequency Diversity

Doubling the Accuracy of Indoor Positioning: Frequency Diversity

A Novel Positioning System Utilizing Zigzag Mobility Pattern

Adaptive framework for uncertainty analysis in electromagnetic field measurements

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